common wire

Hi, My old mercury thermostat (2 wired) recently died and replaced it with a Nest Thermostat 1st Generation (2020). I have a Burnham ES2 Series gas fired boiler (Model # ES24BNI-T). After installing my Nest thermostat gave me an error N260 indicating that a C wire is needed. My thermostat is...

Hi All - new to the forum and would appreciate some expert guidance I would like to install a Nest to control the boiler. the old thermostat used 2 wire (R & W), which are connected to CN10 on the NHB board. I have added a blue and green wire to provide power to the thermostat but don't know...

I’m trying to install an ecobee thermostat. My furnace wiring has a red wire at the C terminal, and white wire at the Y terminal which I assume run to the condenser unit because they are bundled together. Then there is the bundle leading to the thermostat. At the furnace the wires are: green on...

Hello experts, I have a new Navien NCB-240 water heater and I want to install a new Sensi wifi thermostat. That thermostat requires a common wire that would supply 24VAC. On the Navien I found a terminal marked CN25, it has three connectors and in the wiring diagram this terminal is marked as...